Internal Combustion Engine (ICE) vehicles will be replaced by Electric Vehicles (EVs) over the coming years. The purchase and use of EVs is poised to rapidly expand in the United States in the near term. It is estimated that as much as 80% of the electrical charging for these vehicles will be accomplished at the owner's residence. The typical charging requirement for EVs, where more than 1-2 hours is available for the process, will be done with a “Level II” charger. A Level II charger provides 220 Volts of charging capability, usually at 30-40 Amps. This is a significant load on the typical U.S. electric energy supply. Almost all U.S. homes have a master panel that provides 200 Amps or less of electric capacity. Many are 125 Amps or 100 Amps, which makes charging an EV a considerable percentage of the available home electric power. The cost of upgrading or replacing the master service panel in the home can be quite expensive, and in some cases, not possible. This choke point and the expense involved in upgrading the home electric service may suppress the ability for a large part of the U.S. population to move to EVs. This problem is exacerbated when the possibility of two or more EVs per home is taken into account.
This same problem may be extrapolated to public charging stations. Just as a home service panel may approach its capacity in serving electrical demands, so too may a commercial site have an electric service panel that is undersized relative to the need when EV charging demand is added.
Level II charging infrastructure requires expensive circuitry and wiring that is dedicated to one EV at a time. It is also the case that EVs will often occupy a parking bay, at home or in a public parking space, for hours after their EV battery packs are fully charged. This underutilizes the costly EV charging infrastructure.